k8s的Ingress

一.Ingress简介

外部访问集群内的服务,可以通过NodePort或LoadBalancer(这通常由云服务商提供),还可以通过ingress访问.

Ingress包含两个组件Ingress Controller和Ingress：

Ingress:将Nginx的配置抽象成一个Ingress对象，每添加一个新的服务只需写一个新的Ingress的yaml文件即可
Ingress Controller:将新加入的Ingress转化成Nginx的配置文件并使之生效

二.安装和配置

1.官方文档:

https://kubernetes.github.io/ingress-nginx/deploy/

2.创建并应用default-backend.yaml

default-backend的作用是，如果外界访问的域名不存在的话，则默认转发到default-http-backend这个Service，其会直接返回404：

[root@master ingress]# cat default-backend.yaml

apiVersion: extensions/v1beta1

kind: Deployment

metadata:

  name: default

  labels:

    k8s-app: default-http-backend

  namespace: default

spec:

  replicas: 1

  template:

    metadata:

      labels:

        k8s-app: default-http-backend

    spec:

      terminationGracePeriodSeconds: 60

      containers:

      - name: default-http-backend

        # Any image is permissable as long as:

        # 1. It serves a 404 page at /

        # 2. It serves 200 on a /healthz endpoint

        image: anjia0532/defaultbackend:1.0

        livenessProbe:

          httpGet:

            path: /healthz

            port: 8080

            scheme: HTTP

          initialDelaySeconds: 30

          timeoutSeconds: 5

        ports:

        - containerPort: 8080

        resources:

          limits:

            cpu: 10m

            memory: 20Mi

          requests:

            cpu: 10m

            memory: 20Mi

---

apiVersion: v1

kind: Service

metadata:

  name: default-http-backend

  namespace: default

  labels:

    k8s-app: default-http-backend

spec:

  ports:

  - port: 80

    targetPort: 8080

  selector:

    k8s-app: default-http-backend

[root@master ingress]#kubectl create -f default-backend.yaml

2.创建并应用nginx-ingress-controller.yaml

[root@master ingress]# cat nginx-ingress-controller.yaml

apiVersion: v1

kind: ReplicationController

metadata:

  name: nginx-ingress-lb

  labels:

    name: nginx-ingress-lb

  namespace: default

spec:

  replicas: 1

  template:

    metadata:

      labels:

        name: nginx-ingress-lb

      annotations:

        prometheus.io/port: '10254'

        prometheus.io/scrape: 'true'

    spec:

      terminationGracePeriodSeconds: 60

      hostNetwork: true

      containers:

      - image: anjia0532/nginx-ingress-controller:0.9.0-beta.7

        name: nginx-ingress-lb

        readinessProbe:

          httpGet:

            path: /healthz

            port: 10254

            scheme: HTTP

        livenessProbe:

          httpGet:

            path: /healthz

            port: 10254

            scheme: HTTP

          initialDelaySeconds: 10

          timeoutSeconds: 1

        ports:

        - containerPort: 80

          hostPort: 80

        - containerPort: 443

          hostPort: 443

        env:

          - name: POD_NAME

            valueFrom:

              fieldRef:

                fieldPath: metadata.name

          - name: POD_NAMESPACE

            valueFrom:

              fieldRef:

                fieldPath: metadata.namespace

          - name: KUBERNETES_MASTER

            value: http://192.168.2.17:8080

        args:

        - /nginx-ingress-controller

        - --default-backend-service=$(POD_NAMESPACE)/default-http-backend

        - --apiserver-host=http://192.168.2.17:8080

[root@master ingress]#kubectl create -f nginx-ingress-controller.yaml

ps:
注意以上master地址,需要配置成正确的地址

三.自定义Ingress

1.创建并应用test.nginx.ingress

[root@master ingress]# cat test-nginx-ingress.yaml

apiVersion: extensions/v1beta1

kind: Ingress

metadata:

  name: test-nginx-ingress

  namespace: default

spec:

  rules:

  - host: test.nginx.ingress

    http:

      paths:

      - path: /

        backend:

          serviceName: nginx-service

          servicePort: 80

[root@master ingress]#kubectl create -f test-nginx-ingress.yaml

rules中的host必须为域名，不能为IP，表示Ingress-controller的Pod所在主机域名，也就是Ingress-controller的IP对应的域名。
paths中的path则表示映射的路径。如映射/表示若访问test.nginx.ingress，则会将请求转发至Kibana的service，端口为5601。

2.查看创建的ingress

[root@master ingress]# kubectl get ingress -o wide

NAME                         HOSTS                ADDRESS        PORTS     AGE

dashboard-weblogic-ingress   test.nginx.ingress   192.168.2.26   80        2m

我们通过以下命令将pod中nginx的配置文件输出到当前目录下看看

kubectl exec nginx-ingress-lb-6glds -it cat /etc/nginx/nginx.conf > nginx.conf

可以看到是一个标准的nginx配置文件

3.验证

#curl -H "Host:test.nginx.ingress"  192.168.2.26/a.html

如果正常,即可输出结果

巴特西